Probabilistic versus deterministic machine learning for credit default prediction: A multidimensional benchmarking study under severe class imbalance
André Engan , Lars Ole Hjelkrem , Morten Risstad
Networks and Heterogeneous Media ›› 2026, Vol. 21 ›› Issue (5) : 1641 -1677.
Deploying machine learning models for credit decisions under regulatory mandates for explainability and reliability requires evaluation frameworks beyond predictive accuracy. Yet, benchmarking studies in credit risk still focus narrowly on the area under the receiver operating characteristic curve (AUC), neglecting probability calibration, uncertainty decomposition, and interpretability. We address this gap by benchmarking ten models, spanning deterministic and probabilistic families, across four evaluation dimensions on a proprietary dataset of 50,819 customers from a Norwegian financial institution. Each customer is represented by 124 consecutive daily account balance observations and a binary 12-month default flag. Across 180 configurations combining five feature engineering modules with four resampling strategies, variational inference-based Bayesian models (Bayesian neural network, Bayesian logistic regression, convolutional-Bayesian neural network) exhibit posterior collapse on this imbalanced tabular dataset, producing near-uniform predicted probabilities and near-zero epistemic uncertainty, particularly under oversampling. Natural gradient boosting (NGB) emerges as the most effective probabilistic model, matching random forest and XGBoost in test AUC (0.80) while providing informative aleatoric uncertainty estimates and economically interpretable SHAP attributions. We further show that feature engineering and resampling effects are non-additive and model-specific, indicating both as first-order design variables in credit risk pipelines. These findings extend the literature to probabilistic evaluation dimensions and provide practitioners with guidance for model selection in regulatory-compliant credit decision systems under similar data conditions. Note that our performance figures represent exploratory upper-bound benchmarks rather than strictly unbiased out-of-sample estimates.
probabilistic machine learning / credit default prediction / uncertainty quantification / class imbalance / SHAP interpretability
| [1] |
European Union, Regulation (EU) 2024/1689 of the European Parliament and of the Council of 13 June 2024 on laying down harmonised rules on artificial intelligence and amending certain Union legislative acts (Artificial Intelligence Act), 2024. Available from: https://eur-lex.europa.eu/eli/reg/2024/1689/oj. |
| [2] |
|
| [3] |
|
| [4] |
|
| [5] |
|
| [6] |
|
| [7] |
|
| [8] |
|
| [9] |
|
| [10] |
|
| [11] |
|
| [12] |
|
| [13] |
|
| [14] |
|
| [15] |
|
| [16] |
|
| [17] |
|
| [18] |
|
| [19] |
|
| [20] |
|
| [21] |
|
| [22] |
|
| [23] |
|
| [24] |
|
| [25] |
|
| [26] |
|
| [27] |
|
| [28] |
|
| [29] |
|
| [30] |
|
| [31] |
|
| [32] |
|
| [33] |
|
| [34] |
|
| [35] |
|
| [36] |
|
| [37] |
|
| [38] |
|
| [39] |
|
| [40] |
|
| [41] |
|
| [42] |
|
| [43] |
|
| [44] |
|
| [45] |
|
| [46] |
|
| [47] |
|
| [48] |
|
| [49] |
|
| [50] |
|
| [51] |
|
| [52] |
|
| [53] |
|
| [54] |
|
| [55] |
|
| [56] |
|
| [57] |
|
| [58] |
|
| [59] |
|
| [60] |
|
| [61] |
|
/
| 〈 |
|
〉 |